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spectrumhead

join:2009-05-03

PPPoE Concentrator for 2000+ users

We are moving to a system for centralizing our PPPoE concentrator for 2000+ sessions.

It is possible to do it on mikrotik but im afraid of the possible negative effect of 2000+ simple queues on the machine.

Is there any vendor apart from mikrotik worth looking at ?



Inssomniak
The Glitch
Premium
join:2005-04-06
Cayuga, ON
kudos:2

You could get rid of the simple queues.

Any modern x86 machine with mikrotik will do 2000 pppoe sessions and Queue trees without issue.
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TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to spectrumhead

Although getting a bit old now, the Cisco 7200VXR series is worth a look.

Something like an NPE-G1 processor module should be able to handle upwards of 5000 sessions. This includes "shaping" each connection to a subscribed rate, which can be passed to the router via AV pairs from a RADIUS server so it can be done on the fly when the user authenticates.

They are quite an abundant platform, I believe it was one of the most deployed router platforms in the world. You can pick up chassis and processors quite cheaply on ebay and from second hand dealers. Cheap enough that you can stock a spare or two in case theres a component failure.

The spec says they should handle 16000 sessions I think, but being a software platform the more stuff you try to do with it, the lower the quantity you will be able to do, so that figure was probably lacking all features bar the bare minimum.

The 7200VXR has been replaced by the ASR1000 series which may also be worth a look depending on how much cash you have to burn. The ASR is an extremely capable platform, capable of many many thousands more sessions.


spectrumhead

join:2009-05-03
reply to Inssomniak

@Inssomniak
I dont really want to use PCQ. I would like RADIUS attributes to handle bandwidth limitations per user automatically so I dont have to create IP pools per subnet per service package.

@TomS
I am currently checking the Cisco ASR and 7200 series. Is there anything equivalent from Juniper ?

Moreover, which method is the best to pass the pppoe sessions to the main access router? I am thinking about L2TP or MPLS. L2TP seems a standard and easy tunneling method but im not sure about performance drawback if any.



Inssomniak
The Glitch
Premium
join:2005-04-06
Cayuga, ON
kudos:2

I use pcq with the address-list parameter assigned by radius server.
No need to do ip pools.

I use mpls VPLS. Works well
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OptionsDSL Wireless Internet
»www.optionsdsl.ca



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to spectrumhead

L2TP is perfectly fine. I know of ISPs in Australia handling hundreds of thousands of ADSL sessions via L2TP. It does introduce overheads (30 bytes or so IIRC), so its best to build your backhaul to support larger MTUs.

From Juniper, the ERX series is their large scale broadband termination box, but you'd probably be looking at this box for tens of thousands of sessions, rather than a couple of thousand. Some of their routers will handle up to 4000 sessions, like the smaller MX series (MX80 and below.)

I cant claim to be an expert on broadband termination with Juniper, so I really dont want to say any more.

What I will say is that if I were looking at rolling out an ISP, I would probably use Cisco for my broadband termination because I am most familiar with it.

I used to know so much more about this, but over the last 2 years of not really doing much with it all Ive forgotten a bit.


jcremin

join:2009-12-22
Siren, WI
kudos:2
reply to Inssomniak

said by Inssomniak:

I use pcq with the address-list parameter assigned by radius server. No need to do ip pools.

I'd be interested in hearing more about your config for doing that. Not sure if it would be too far off topic for this thread.. if so, would you mind PM'ing me with a bit more info, or posting it into another thread?

Thanks,
Joe


DaDawgs
Premium
join:2010-08-02
Deltaville, VA
reply to spectrumhead

said by spectrumhead:

We are moving to a system for centralizing our PPPoE concentrator for 2000+ sessions.

PPPoE being a layer two protocol will naturally load balance across concentrators. When the PADI is sent all the servers see it at the same time but the one that is the least loaded will send the first PADO. The client always goes for the first PADO it sees that matches the service name.

So when I needed another 100 or so PPPoE sessions at any of our PoPs I would just put a switch in the setup and stick another PPPoE server on the switch.

They naturally load balance because response time of the concentrator reduces when it is heavily loaded. This implies that you can even have different PPPoE hardware ganged on a switch and the weakest one will carry only the number of users that it should.

I had one PoP that had about 300 subs on 3 RB433AH units with queues and traffic shaping running on every one of the devices. They load balanced like they were talking to each other... +)
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bates

join:2013-02-20
reply to jcremin

said by jcremin:

I'd be interested in hearing more about your config for doing that. Not sure if it would be too far off topic for this thread.. if so, would you mind PM'ing me with a bit more info, or posting it into another thread?

Thanks,
Joe

It's done by passing back the Mikrotik-Address-List attribute from radius on authentication.

Mikrotik-Address-List=<your list here>

Mikrotik attribute for your radius dictionary:
ATTRIBUTE Mikrotik-Address-List 19 string

jcremin

join:2009-12-22
Siren, WI
kudos:2

Cool, I'll check that out. Thanks!



Inssomniak
The Glitch
Premium
join:2005-04-06
Cayuga, ON
kudos:2

Yes exactly this. Then standard issue PCQS using address list as qualifier for marks
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OptionsDSL Wireless Internet
»www.optionsdsl.ca